This Renewal Application for NRSA T32 MH20031 seeks to continue a highly successful Pre- and Post- Doctoral Fellowship Training Program (established in 1999) in HIV prevention research at Yale University's Center for Interdisciplinary Research on AIDS (CIRA). Over the past ten years we have successfully trained Post-Doctoral Fellows, with younger, early-career scientists thriving in our Pre-Doctoral Training component over the past five years. CIRA, housed within the School of Public Health at Yale University, provides an exceptional training environment that continues to keep step with the changing HIV/AIDS pandemic. Our training program is unique in providing the following combination of perspectives: a focus on vulnerability and underserved populations; a strong foundation of training that emphasizes methodological rigor in both quantitative and qualitatative analyses; opportunities to conduct ethically sound, community based research, domestically and internationally; and emphasis on legal, policy and ethical analysis of HIV prevention science. We are requesting support for 4 Pre-Doctorate and 7 Post-Doctorate slots per year. The Pre- Doctorate training program consists of: formal course work, research preceptorship, seminars, outside courses and meetings, qualifying examinations, and dissertation research. The focus of the Post-Doctorale Fellowship is hands on conduct of research, analysis, paper and grant writing with a faculty mentor. Our approach to training future scientists for careers in HIV prevention research will emphasize flexibility and individual tailoring of Fellows' course work research preceptorships, while recognizing the importance of core training in methodology and ethics. Over the past 10 years we have successfully trained, and continue to train, 29 post-doctoral fellows and 6 pre-doctoral fellows covering a wide array of disciplines. Fellows were both exposed to and actively collaborate in a wide array of studies, publication records and career trajectories. We are, therefore, confident in our ability to prepare both Pre- and Post-Doctoral Fellows with the strongest foundation of knowledge, skills, and experience to achieve and sustain careers as scientific investigators, contributing to advances in HIV prevention, specifically, and public health, in general. RELEVANCE (See instructions): The objective of our Training Program is to provide the strongest foundation of knowledge, skills, and experience to young investigators at the pre- and post-doctoral levels, who can establish (and sustain) careers as scientific investigators, contributing to advances in HIV prevention, specifically, and public health, in general.